Live Salmonella typhi vectors engineered to express heterologous outer membrane protein antigens and methods of use thereof

Abstract

The present invention provides compositions and methods of inducing an immune response in a subject in need thereof, comprising administering to the subject an immunologically-effective amount of a live Salmonella Typhi vector comprising a heterologous antigen from a pathogen, wherein the heterologous antigen comprises an outer membrane protein, an antigenic fragment thereof or a variant thereof, wherein the antigen is delivered to a mucosal tissue of the subject by an outer membrane vesicle.

We claim: 
     
       1. An immunogenic live  Salmonella  Typhi vector that has been engineered to express one or more heterologous antigens from a pathogen, wherein the heterologous antigen comprises outer membrane protein OmpW or an antigenic fragment or variant thereof and comprises outer membrane protein OmpA or an antigenic fragment or variant thereof, wherein the live  Salmonella  Typhi vector is capable of delivering immunogenic, recombinant outer membrane vesicles (rOMVs) to a mucosal tissue when administered to a subject, wherein the vesicles comprise the heterologous antigens, wherein the  Salmonella  Typhi vector has been engineered to overexpress a lipid A deacylase PagL. 
     
     
       2. The  Salmonella  Typhi vector of  claim 1 , wherein the pathogen is selected from  Acinetobacter baumannii  and  Klebsiella pneumoniae.    
     
     
       3. The  Salmonella  Typhi vector of  claim 1 , wherein the outer membrane proteins are each encoded by a nucleic acid sequence that is chromosomally integrated in S. Typhi. 
     
     
       4. The  Salmonella  Typhi vector of  claim 1 , wherein a homologous S. Typhi outer membrane protein has been deleted or inactivated. 
     
     
       5. The  Salmonella  Typhi vector of  claim 1 , wherein the outer membrane proteins each encoded by a nucleic acid sequence are each inserted into an S. Typhi locus selected from the group consisting of guaBA, rpoS, htrA, ssb, and combinations thereof. 
     
     
       6. The  Salmonella  Typhi vector of  claim 1 , wherein at least one outer membrane protein encoded by a nucleic acid sequence is inserted into the rpoS locus of S. Typhi. 
     
     
       7. The  Salmonella  Typhi vector of  claim 1 , wherein the outer membrane protein OmpW encoded by a nucleic acid sequence is chromosomally integrated into the guaBA locus. 
     
     
       8. The  Salmonella  Typhi vector of  claim 1 , wherein the outer membrane protein OmpA encoded by a nucleic acid sequence is chromosomally integrated into the rpoS locus. 
     
     
       9. The  Salmonella  Typhi vector of  claim 1 , wherein the OmpA comprises one or more mutations. 
     
     
       10. The  Salmonella  Typhi vector of  claim 9 , wherein the mutation comprises one or more substitution mutations selected from D271A and R286A. 
     
     
       11. The  Salmonella  Typhi vector of  claim 9 , wherein OmpA comprises both D271A and R286A mutations. 
     
     
       12. The  Salmonella  Typhi vector of  claim 1 , wherein the S. Typhi overexpresses a cytolysin A (ClyA) protein to facilitate outer membrane vesicle formation. 
     
     
       13. The  Salmonella  Typhi vector of  claim 12 , wherein the ClyA is mutated to reduce hemolytic activity of ClyA. 
     
     
       14. The  Salmonella  Typhi vector of  claim 13 , wherein the ClyA mutant is selected from the group consisting of ClyA I198N, ClyA A199D, ClyA E204K, ClyA C285W and combinations thereof. 
     
     
       15. The  Salmonella  Typhi vector of  claim 12 , wherein the ClyA is a fusion protein. 
     
     
       16. The  Salmonella  Typhi vector of  claim 15 , wherein the ClyA comprises I198N, A199D, and E204K substitution mutations. 
     
     
       17. The  Salmonella  Typhi vector of  claim 1 , wherein the PagL amino acid sequence is selected from SEQ ID NO:2 and SEQ ID NO:4. 
     
     
       18. An immunogenic composition comprising a combination of the live  Salmonella  Typhi vectors according  claim 1 , wherein a first  Salmonella  Typhi vector expresses i) OmpA, an antigenic fragment thereof or a variant thereof from  Acinetobacter baumannii ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from  Acinetobacter baumannii  and a second  Salmonella  Typhi vector expresses i) OmpA, an antigenic fragment thereof or a variant thereof from  Klebsiella pneumoniae ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from  Klebsiella pneumoniae.    
     
     
       19. An immunogenic composition comprising isolated recombinant outer membrane vesicles from the  Salmonella  Typhi of  claim 1 , comprising one or more heterologous antigens from a pathogen, wherein the heterologous antigen comprises an outer membrane protein, an antigenic fragment thereof or a variant thereof, wherein the  Salmonella  Typhi has been engineered to express the heterologous antigen. 
     
     
       20. An immunogenic composition comprising a combination of the isolated recombinant outer membrane vesicles of  claim 19 , wherein a first isolated recombinant outer membrane vesicle comprises i) OmpA, an antigenic fragment thereof or a variant thereof from  Acinetobacter baumannii ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from  Acinetobacter baumannii  and a second isolated recombinant outer membrane vesicle comprises i) OmpA, an antigenic fragment thereof or a variant thereof from  Klebsiella pneumoniae ; and ii) OmpW, an antigenic fragment thereof or a variant thereof from  Klebsiella pneumoniae.